Tuning and indicating apparatus for radio receivers



June 21, v I J. TUNING. AND mm'cmine APPARATUS FOR RADIO'VRECEIVERSFiled June 29, 1936 s Sheets-Sheet June 21, 1938. L. J. WRONKE 2,121,767

TUNING AND INDICATING APPARATUS FOR RADIO RECEIVERS Filed June 29, 19363 Sheets-Sheet 2 O If x June 21, 1938. J, WR N 2,121,767

TUNING AND INDICATING APPARATUS FOR RADIO RECEIVERS Filed June 29, 19363 Sheets-Sheet 5 [May aw? Patented June 21, 1938 TUNING AND mwimeAPPARATUS Eon more nEcEIvEns Louis J. Wronke,Ohicago,1ll.. assignmtoBel.-

mont Radio Corporation, Chicago, 111., a

i poration of Illinois Application June 29, 1936. Serial Na. 87,892

Claims.

This invention relates to dial ap ratus especially suitable for radioreceiving sets, together with a mounting for such apparatus.

It is an object of the present invention to pro-' vide a more economicaland satisfactory support and housing for the dial anddial apparatus thanhas heretofore been known] This'is accomplished by using a single pieceof metal drawn to shape as a complete support and housing. The drawnmember also serves as a reflector and mounting for the dial lights toilluminate the dial.

Another object of the .inventionis to provides.

simplified form of indicator for indicating, some fact other than thatindicated by the main dial, such as the wave band on which the set isoperated. This is accomplished by providing a perforated disc rotated bythe band'control switch to illuminate different slots in the dial.

A further objectof the invention is to provide a3 dial havingindependent calibrations for short wave reception and broadcastreception, together with means for indicatingwhich of said bands the setis adjusted to receive, the calibrations" and the .wave band indicatorbeing so correlated as to,

facilitate choosing the proper scale of calibra- 3 tions in reading thedial. Thus, in the ilIustrated form the slot indicator fo'r'e'achfrequency bandis alined with the calibrations for that band.

Another object of the invention is to provide with little additionalcost a micrometer indicator for indicating the position of thecondensersmore accurately than is possible with the-main hand on the ordinarydial. According to the present invention such a micrometer indicator ismounted on the pinion driving the gear segment connected to the mainneedle. An additional object of the invention is to provide a simplifiedcombination of condenser frame and control mechanism mounting with acorresponding reduction in cost of production.

Another object of the invention is to decrease the current consumptionof radio receiving sets; first, by providing a housing for the dialappad ratus of such nature that it is a good reflector so that adequatedial illumination may be obtained by a single lamp even though the dialis relatively large; and second, by providing means for automaticallyturning the dial light oil, except during tuning. This last namedfeature is ac-,

complished by normally open contacts closed by the tuning knob of thereceiver so that'the dial may be illuminated .very easily, wheneverdesired. The saving of current drain due; to the dial light is, ofcourse, especially valuable when 7 section, of a modification of,

in automobile receiving sets, when excessive cur- H rent consumption maycause great inconvenience.

Additional objects and advantages of my invention will be apparent fromthe following description, taken with the drawings, in which:

Fig. 1 is a front view of the dial assembly. N Fig. 2 is a side viewofthe same. showing its connection to the condenser frame. 1 1 Fig. 3 isa bottom view of the same with a portion broken away. a

Fig. 4 is a sectional view of the same, taken substantially along theline 4-4 of Fig. 2."

Fig.5 is afragmentary sectional view, showing the mouhting of themicrometer'indicator' and driving pinion.

Fig. 6 is'a front view of the mounting bracket 7 for the mechanismillustrated in Fig. 5.

Figs. 10 and 11 are fragmentary sectional views taken substantiallyalong the line Ill-i 0 of Fig. 7, showing two forms of dial lightswitches.

Fig. 12 is a fragmentary side view, partly in Fig. 5. (p g a. Althoughthisinvention may take numerous forms; only a few have been chosen forthe pur- In all of these forms the pose of illustration.

apparatusare supported dial and part of the by a drawn metal supporthousing ll, which in cludes a cupped portion i2 secured to the tu n. ingcondenser frame of the receiving-set. .In the form shown in Fig. 1 it-lssecured to the end plate i3 of the condenser frame. Covering the frontside of the cupped portion i2 is a dial 16, preferably of translucentnature and inscribed with suitable wave length or frequency mark:

the structure of ing which aresuitably illuminated- In'Fig. 4 I

the dial is illuminated from the back by two lamps l5. reflecting theirlight of! of the sides and rear.

of the housing. As a matterof fact the, house by the condenser shaft" 18,.

I 0 ing II is such a good reflector that a single lamp trated in Fig.12. This includes the pulley 23.

mounted on a bearing shaft 200, carrying a spur gear 2M. A brass bearingplate 202 is secured .to

the end plate It of the gang condenser, and has a tapered hole 203centrally thereof tosupport the tapered end of the shaft 202. Asubstan-" tlally U-shaped bracket 288 with both legs secured to thebearing plate and end plate supports the entire assembly.

The dial I6 is printed in reverse with an opaque ink with the indicialeft clear so that the indicia are illuminated on a dark background. Forsimplicity of illustration, the black and white parts of the dial havebeen reversed within the line 28 in the drawings, so it should beunderstood that the entire face of the dial withinthatline is blackexcept for the figures and lines which have been shown'black, which onthe actual dial are left white. The part of the dial outside of the line23 will of course be hidden by an escutcheon plate or other shield.Within the escutcheon the indicia will be illuminated from behind by thelamps l6.

A second control knob may be mounted on a shaft 3|, which may operate aswitch 30 .for shifting the receiving apparatus from one frequency band,as the broadcast frequency band, to another frequency band such as theshort wave band. A wave band indicator disc'33 is rotatably mounted onthe housing l2 by a rivet 35 holding the disc in engagement with atension washer (not shown), and said disc is connected to the shaft 2|to be rotated by it. This connection is accomplished by means of a crank39 disc so that the crank-link mechanism is inv effect a bell-crankconnection between the switch shaft and disc to place the openings 34 inthe latter in the proper position for wave band indication as the waveswitch is rotated. The plureality of slots 34 are covered by atranslucent strip 34 and sopositioned that for each wave band to whichthe receiving apparatusmay be adjusted light shining through the slots34 shines through one of the various slots 38 in the dial l6. It willbeobserved that each of the wave band indicating slots 38 is alinedwithone of the three calibration lines. This makes it very easy for theuser to know which of the three calibration lines he should read, sincehe reads the one alined with the illuminated slot 38. The knowledge ofwhich calibration line to read is made still more clear by thearrangement of colors on the back of the dial. Thus, a strip 4| of onecolor such as green is applied behind the inner short wave line ofcalibration 39 and a' strip 42 of another color such as red is appliedbehind the middle calibration line 39. A green strip or a strip of athird color may be applied behind the outer or broadcast calibrationline, or, as illustrated, it may be left white. The colored strips 4|and 42 may be bands of translucent The link paint or a separately formedstrip of translucent material. They may be applied by a printingprocess, or they may be sprayed or brushed on through stencils. Theinner zone of color 43 is merely decorative. Since the dial isilluminated from behind by lamps ii, the color on the back will beimparted to the lines 'as seen from the front, and the light isprevented from shining through the dial except along the desired linesand to show the desired indicia by the opaque ink printed on the face ofthe dial as previously mentioned. I

Although a single strip 34' has bee illustrated as covering all threeslots 34, it she d be obviousthat they may each be covered with atranslucent strip corresponding in color to the color of the particularcalibration strip 39 which it designates. Even without this, however,the fact that the three calibration lines are differently colored makesthem very easily followed, and the user very soon becomes so accustomedto the dial that without any conscious effort he reads the right line ofcalibration as indicated by the particular slot 38 which is illuminated.

The general construction of the apparatus will be sufllciently clear inview of the foregoing rather general description, but a few of thedetails may also be described in case they may not be self-evident fromthe drawings. It should be recognized, however, that each of the novelfea tures can be used with variations as to the other features. Forexample, various types of drive mechanism may be used in place of thatshown.

As has been stated, the support housing I I is a single piece of metaldrawn to the desired shape. If it is to be attached to plate 13 it isprovided with three attachment bosses 5| pressed out from the bottom ofthe cupped portion l2. In Fig. 2 all three of these bosses are shown,while in Fig. 3

. it may be understood that on the right side is seen the boss shown atthe middle of Fig. 2, while on the left side are both the bosses shownat the top and bottom in Fig. 2. These two bosses are in alinement sothat only one shows. Screws 52 fitting in said bosses to rigidly fastenthe housing ii to the condenser frame l3 are shown in dotted lines inFig. 1, to more clearly indicate the position of the three bosses, whichpositions are chosen so that these elements may be secured firmlytogether without any danger of applying distortional strain to thecondenser frame. The

- plate i3 be omitted, and a support housing II I be provided which iscapable of serving the functions of the plate I3-as well as its otherfunctions, as shown in Fig. 9. This is of course a more economicalconstruction.

Support housing I I maybe punched to provide any required openings,including the'opening 56 in the bottom of the cupped portion l2, theopening 51 in the back of the cupped portion l2, the openings for thecontrol shafts 21, 3|, the openings for the lamps l5, as well as thenumerous small openings that are necessary for the attachment of parts.The belt 24 will extend downwardly through the opening 58, and the gearmechanism may be supported on the condenser frame and extend throughtheopening 91, al-

though, if preferred, the gear mechanism could be supported by thesupport housing, II. Although the gearing has been shown positionedwithin the housing in Fig. 3, it may be positioned behind the end plateI3, or behind the housing H or the housing II I as'seen in Fig. 9.

If back-lash or play is present between the variable condenser andgear-mechanismdriving the dial, which gear mechanism is actuated by acontrol knob, it is impossible to get accurate readingson the dial,and'it also affects the accuracy of thetuning control of the receiver.The constructionof the split gearsegment' I9 is such as to eliminatethisback-lash or play between it and the pinion 2|. The gear includes twosegments side byside, one of which is keyed to the shaft I8 and theother of which is urged by a spring 6| toward. a different angularposition, with the result that theteeth of pinion 2I are squeezedbetween the respective teeth and the two segments comprising the splitsegment I9;

Although this feature alone eliminates all backlash between theindicating needle, the micrometer indicator, and the condenser, it isalso desirablethat back-lash be eliminated between these members and themanually turned shaft 21. This is accomplished by providing a springbelt tightener including pulley 62 carried by an arm t8 forming anextension of a coil spring 8| carried by a suitable peg 88, whim may besecured to the support, housing II in any suitable manner, as by acrimped split washer on the back of the housing. The tension on the arm83 should be enough so that'there will be no appreciable backlash in thebelt 24, as the shaft 21 is turned in opposite directions. One advantageof the belt tightener is that it permits positioning the shaft 21 at oneside as seen in Fig. 7, when desired, while holding the belt away fromthe other working parts.

As seen in Fig. 5, the shaft 20 carrying pinion 2I, pulley 23, andmicrometer indicator 22 is preferably journaled in a bracket, which maydesirably be a U-shaped bracket so as to support the rotating structureon opposite sides of the pinion H. The bracket 68 may be secured bysuitable screws Hi to the condenser frame I3 with intervening spacerposts 89 to hold it at the proper position. Of course, when the pinion 2I is ,on one s de ofthe housing I l I (or plate I 3 J and the pulley 28on the other, the specialbracket 68 may not be necessary, especially ifa bushing 15 is secured to the housingIII for journaling the shaft whichthe pinion 2 I; is carried.

through a suitable hole in the dial I 6. To prevent leakage of lightbetween the disc 22 and the dial I6, the-disc may be provided withanoutwardlyextending flange 83 which'overlaps the sides of the hole formedinthe dial. I

The lamps I may conveniently be mounted insockets II, which aresupported by the housing support II by means of being inserted throughrubber grommets I2. Thisavoids any electrical connection between thedial light and the condenser frame. provided, as in Figs. 7 and 8, thelamps will be positioned with their-filaments in alinement with theglass I I6 as there shown. It has been found, in the commercialembodimentiof the invention, that the edge illumination from the topwillcarry When edge illumination is to be:

the dial is such that additional illumination is desired, a lamp I22 maybe mounted at the top and in the center as shown in Fig. 8. I

It has long been recognized that dial lamps consume an undesirableamount .of current, especially'in an automobile when there may betrouble in keeping the battery sufliciently charged. It has been thecustom in the past to have the dial lamps lit whenever the set is operating. However, the only time when the lamps are needed is when the setis being tuned, and, therefore, the present invention. contemplates aconvenient means for having the lights lit whenever illumination oi! thedial is desired for tuning and having them turned off at all othertimes. As seen in Figs. land 7, a pair of contacts 88 are positionednear the tuning shaft 21. The arrangement of these contacts 88 and theassociated parts is seen best in'Figs. and 11, in which twomodifications of the associated parts are shown.

In Fig. 10 it is seen that the shaft 21 is carried by'abushing81 securedto the housing I I in any suitable manner, as by being peened over inthe hole therethrough; as shown. This shaft 21 may be slidablyJournalled in the bushing 81 or not, as preferred. In Fig. 10 thecontrol knob "is provided with a tubular sleeve 88- iitting over the.shaft 21 and slidable thereon, with sliding movement being limited by apin 88. The sleeve 88- bears against an insulating button 82 slideable'contacts 86 and completes .the circuit to the diallamp or lamps IS.

A similar, but somewhat simplified, arrangement is shown in Fig. 11, inwhich the structureis substantially the. same except that the sleeve 89is omitted. In this instance the entire shaft 2! slides in the bushing81in response to pres-,

sure on the knob 88 with the same result of pressing the contact washer88 against the contactsBB. Theshaft 21 and the contact washer 98 areboth pressed outwardly by the spring washcrill. d

When this contact arrangement is used, it is especially desirable thatthe depending portion of the housing II be'adequately rigid. For thispurpose it may bestifiened by ribs 88. preferably depressed -in oppositedirections to obtain the greatest stiffening effect. The entire frontflange of the support housing member is stiffened by a peripheral flange8|.

Some reference has already been made to the edge illumination featuresshown in Figs. 7 and 8. The principle of edge illumination is already.

well known and need not be fully described.

' Preferably a may b'e stated that light from'the lamps I I6 passes intothe edge of the glass dial II6, which bears suitable indicia. Exceptwhere it strikes theseindicia, the light within the glass is notnoticeable. A black backing plate may be provided if desired, as if sometranslucent indicators such as the micrometer indicator Here [to be usedpositioned adjacent holes in the backing plate ,III. r i

The housing II lends itself admirably to the use ofdial illumination,since the lamps may be mounted near the edge thereof, as shown in Fig.8, and since the glass dial H8 may very easily 7 over the entire dial,but if the size or nature of be upp rted in the h g y, providing stampedout lugs 8 on which the glass may rest and by providing opening H9 inwhich clips I 20 may be inserted, as seen best in Fig. 8.

The reference character IZI designates an es-- cutcheon plate for thedial and cabinet, Fig. 8,

illustrating how the dial and dial lamp are posi- V tioned with respectto said plate.

From the foregoing it is seen that a dial-tuning assembly mechanism andmounting combination is provided which at the same time is both econotonly the main indicator needle but also a micrometer indicator.Furthermore, this construction provides for a main tuning indicator, andvernier indication with two separate pointers, on separated shafts, andin its simplicity is even less expensive than the single concentricshaft construction heretofore employed in the art. The present mechanismmakes for more accurate tuning than the prior structure. though the mainindicator needle moves along three lines of calibrations, the correctone to be read is made obvious by an illuminated slot alined therewith.The various lines of calibrations are further distinguished bydistinctive coloring. A simple disc with a plurality of slots in it isthe means for selectively illuminating one of the slots.

Although the preferred form of my invention has been herein shown anddescribed, it is to be understood that the invention is not limitedthereby, but is to be limited only by the'prior art. The followingclaims are intended to point out some of the features now recognized asnew, rather than to limit the invention to these features, except as maybe required by the prior art.

I claim:

1.. The combination of a radio tuning condenser having a condenserframe, a condenser shaft rotatable with respect'thereto for adjustingthe condenser, a housing support member drawn from a single piece ofsheet metal and including a rearwardly cupped housing portion secured tosaid condenser frame, and an extension to one side of said cuppedhousing portion a dial secured to said cupped housing portion, an

indicator movable with respect to said dial, and

mechanism for moving said indicator supported entirely by the supportstructure including said housing support member and extension and saidcondenser frame, said mechanism including a ear segment mounted on saidcondenser shaft on which said indicator is also mounted, and a pinionengaging said gear segment and carried by a shaft spaced radially fromsaid condenser shaft and independent thereof, and a micrometerindicator.visible from in front of the dial operating over a micrometerscale and carried by said pinion shaft.

. 2. A dial apparatus for a radio receiving set adjustable to receivesignals on a plurality-of bands of wave lengths with the same main dialsettings, including a dial and an indicator mov-' ceiving ,set, saiddial also having a plurality of windows therein so positioned that oneof said dial windows is alined withone of said disc windows for eachadjustment of the set.

3. A dial apparatus for a radio receiving set adjustable to receive on aplurality of bands of wave lengths with the samemain dial settings,including a dial and an indicator movable with respect .thereto, saiddial having a plurality of lines of calibrations along which saidindicator moves simultaneously, and means for indicating which of saidlines of calibrations should be read for the particular adjustment ofthe set, including a disc having a plurality of windows therein, meansfor moving said disc in accordance with the adjustment of said receivingset, said dial also having a plurality of windows therein so positionedthat .one of said dial windows is alined with one of said disc windowsfor each adjustment of the set, each of-said dial windows being inalinement with the line of calibrations corresponding thereto.

4. A dial apparatus for a radio receiving set adjustable to receive on aplurality of bands of wave lengths with the same main dial settings,including a dial and an indicator movable with respect thereto, saiddial having a plurality of lines of calibrations alongwhich saidindicator moves simultaneously, and means for indicating which of saidlines of calibrations should be read for the particular adjustment oftheset, including means for providing a visible indicationsubstantially'in alinement with both ends of the line to be read and.intermediate said ends, and means for imparting distinctive indicatingcolors to-said lines of calibrations.

5. The combination of a radio tuning mechanism including a dial, a drawnmetal support housing for said dial, and a control knob mounted thereonfor both rotative and axial movement and biased toward one axialposition, a dial light for illuminating said dial, and a switch for saidlight closed by axial movement of said knob away from its biasedposition; said switch including a pair of contacts insulated from andsupported by said support housing, and a bridging contact operated bysaid knob but: insulated from said housing.

6. Apparatus for controlling the tuning of a radio receiver andindicating the tuned position thereof, including a dial having aplurality of tuning scales thereon, with each of said scalescorresponding to a single wave band for radio reception and following a.path closed over the greater part of the length thereof and interruptedat one point therein byaviewing spacaan indicator movable oversaid dial,tuning means for operating said indicator, and a single member operatingbehind said dial and providing an indication visible throughsaid-viewing space to indicate which of said scales is being utilized inthe tuning of said radio receiver.

7. Apparatus for controlling the tuning of a radio receiver andindicating the tuned position thereof, including a dial having aplurality of tuning scales thereon, with each of said scalescorresponding to a single wave band for radio reception andfollowingapath closed over the greater part of the length thereof andinterrupted at one point by'a viewing space, an indicator movable oversaid dial, tuning means for operating member movable to bring saidaperture into alinement witha viewing space in the dial whereby thecolor or said material is visible through a viewing space in said dialto indicate the particular scale being utilized in the tuning of saidradio receiver.

'8. A multi-band radio receiver having a wave band change-switch, a dialhaving a plurality of tuning scales thereon, lighting means to the rearof the dial, a sight opening in the path of each tuning scale, anindicator member movable in back of said sight openings having aplurality of translucent portions therein corresponding in number to thenumber of tuning scales, and means operable by said band change switchto move said indicator member to position a translucent portion behind acorresponding sight opening to permit light to shine through saidportion and said opening to indicate the wave band being utilized. 7

9. A compact tuning and indicating apparatus for a multi-wave band radioreceiver including a tuning condenser, a dial plate with a plurality oftuning scales thereon, indicating mans ineluding an indicator movableover said scales, a wave-band indicator movable to the rear of said dialplate and rotatable control shaits having connecting means to both saidindicators and condenser, anda one-piece frame for supporting saidcondenser, dial plate and indicating means with connected controlshafts, said frame comprising a cupped housing with 1 the condensersupported directly on the rear thereoi,-withsaid wave-band indicatormovable therein behind the dial plate thereon, and an integral dependingflange from said cupped portion for supporting said control shafts.

i0. Indicating apparatus for a multi-wave band radio receiver includingadial member having a plurality of tuning scales thereon. a plurality ofviewing spaces on said member corresponding in number to the number oftuning scales, a disc rotatable behind said dial member having means toprovide scale indication selectively visible at a viewing space, acontrol shait spaced from said disc and eccentric connecting meansbetween said shaft and disc comprising a pair of pivoted arms with onearm rigidly secured to said shaft and the other arm pivoted to said discat a point adjacent the outside edge thereof.

IDUIS J. WRONRE.

